Ocium basilicum essential oil biostimulant activity and protective effects on cadmium-induced DNA damage and oxidative stress in Raphanus sativus L

The ability of the essential oil (EO) of the aerial parts of Ocimum basilicum L. cv 'Prospera' and its main constituents to reduce cadmium (Cd) toxicity in Raphanus sativus L. was tested. To study the tolerance induced by EO to Cd toxicity, the percentage of seed germination and hypocotyl-root length, DNA damage and antioxidant response were examined. The exogenous application of EO produces a recovery in the percentage of seed germination and hypocotyl-root length; it also reduces Cd-induced oxidative stress, as demonstrated by the reduction in the content of reactive oxygen species (ROS) and the increased activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST). Furthermore, the application of EO produces a reduction in DNA damage. To investigate these promising results, both enzymatic activity and DNA damage were individually evaluated by testing the most common constituents in EO: endo-fenchol (21.5 %), eugenol (20.4 %) and carvacrol (10.2 %). These compounds replicated the antioxidant and genoprotective effects observed with the whole oil, with endo-fenchol and eugenol showing the strongest activity. Our findings clearly demonstrate that O. basilicum EO possesses a potent bioprotective effect against Cd-induced oxidative stress and genotoxicity, acting both through enzymatic activation and the inherent antioxidant properties of its major constituents. This study supports the use of basil EO as a natural, sustainable strategy to enhance plant tolerance to heavy metal stress, with promising applications in environmental and agricultural biotechnology.